The ability to modify the surface of a solid material such as glass has facilitated many biomedical and chemical applications.1,2,3,4,5 
Known methods of modifying planar surfaces such as glass surfaces include a wide range of non-contact methods such as inkjet printing,6 photolithography,7 and plasma deposition.8,9 
These non-contact modification methods do not, however, work so well on non-planar surfaces. For example, the inside of a glass microchannel is far less amenable to these patterning methods.10 Therefore, the modification of the inside surface of glass microchannels has used soft lithography methods such as microcontact printing.11 However, as these soft lithography methods can only be used on exposed channel surfaces before sealing, the properties of the modified surfaces need to be compatible with any subsequent sealing process, for example, high-temperature fusion bonding of glass onto glass.
It is also known to use photolithographic methods to pattern the surface of a solid material such as glass. In order to work, the wavelength of the light used in the photolithographic method must not be fully absorbed by the solid material. In addition, the more of the light that is absorbed, the less well the photolithographic method works (i.e. the photolithographic method will work to a lesser extent). Therefore, photolithographic methods are limited by the degree to which the solid material (and the reagents used in the method) absorbs the light.
These limitations concerning the photolithographic method are particularly relevant when attempting to pattern the internal surface of a structure such as a glass microchannel. In such methods, the light is applied from the outside of the structure. Therefore, if the light is substantially absorbed by the structure itself, no patterning will occur on its internal surface. As a result of these limitations, commonly used glass modification chemistries like phosphonic acid,13 or catechol-based14 approaches do not allow a photolithographic process to be carried out on the inside of a glass microchannel.12 
The photochemical attachment of alkenes to glass surfaces has allowed the local formation of densely packed, stable organic monolayers with reactive functional groups onto exposed surfaces,15,16 for example, onto the inside of a glass microchannel.17 This has enabled, for example, the subsequent local attachment of fragile biologically active materials, such as DNA-enzyme hybrids which could then be used to construct an enzyme cascade in a microchannel.18 In order to perform the photochemical attachment of the alkenes, this photochemical reaction was limited to wavelengths lower than 285 nm.
At wavelengths of 285 nm or less many organic moieties start to undergo photochemical transformations. In addition, some solid materials, for example, glass, absorb a significant portion of light with wavelengths lower than 285 nm. As well as hindering the photochemical reaction, the absorbance of light by the solid material may heat this material allowing secondary reactions to take place. Finally, alkene attachment at wavelengths of 285 nm or smaller also yields multilayer formation for many functional groups.19 In some cases, multilayer formation can be disadvantageous because of reduced reproducibility on the molecular scale.
The present invention is, therefore, directed towards an improved method for modifying the surface of a solid material. This improved method may at least partially avoid one or more of the disadvantages mentioned above. Preferably, the method of the present invention can be used on both planar and non-planar surfaces.